Patients' radiation doses during percutaneous endovascular procedures in arteries of the lower limbs.

BACKGROUND: Percutaneous endovascular revascularisation interventions are increasingly used in treatment of lower extremity artery disease and may expose patients to substantial radiation. PATIENTS AND METHODS: Dose-area product (DAP) was retrospectively analysed in 1063 consecutive interventions performed in adult patients with lower extremity artery disease in a single tertiary medical centre. Differences between procedure types, stratified according to anatomical region and arterial lesion complexity were evaluated. RESULTS: Median DAP for diagnostic interventions was 35.6 (15.0-52.4) Gy cm2 in aorto-below-knee arteriography and 3.2 (2.0-4.5) Gy cm2 in ipsilateral femoral arteriography (p < 0.001). For angioplasty without stenting, median DAP was 53.4 (28.6-87.4) Gy cm2 for pelvic interventions vs. 5.9 (4.3-8.6) Gy cm2 for antegrade ipsilateral femoropopliteal interventions (p < 0.001). For stenting, median DAP was 54.9 (32.5-91.2) Gy cm2 for pelvic interventions vs. 8.3 (6.0-12.3) Gy cm2 for antegrade ipsilateral femoropopliteal interventions (p < 0.001). Inside the same anatomical region, diagnostic interventions were associated with significantly lower DAP than therapeutic interventions. Stenting vs no stenting increased DAP values only in antegrade ipsilateral femoropopliteal interventions (8.3 (6.0-12.3) vs 5.9 (4.3-8.6) Gy cm2 (p < 0.001). Arterial lesion complexity affected DAP values only in antegrade ipsilateral femoropopliteal therapeutic interventions. CONCLUSIONS: The most important factor influencing patients' radiation doses was the anatomical region. Pelvic interventions were associated with 6-11-times higher DAP values than femoropopliteal interventions with antegrade ipsilateral approach. Stenting and complexity of lesions increased DAP only in antegrade ipsilateral femoropopliteal interventions.

18F-choline PET/CT for parathyroid scintigraphy: significantly lower radiation exposure of patients in comparison to conventional nuclear medicine imaging approaches.

BACKGROUND: Parathyroid subtraction scintigraphy (PSS) is the most commonly used imaging method for localisation of hyperfunctioning parathyroid glands (HPGs) in primary hyperparathyroidism (PHP), a common endocrine disorder. Hybrid (SPECT/CT) imaging with 99mTc-sestaMIBI (MIBI) at an early and delayed phase (dual-phase imaging) may be the most accurate conventional imaging approach, but includes additional radiation exposure due to added CT imaging. Recently, 18F-choline (FCH) PET/CT was introduced for HPG imaging, which can also be performed using the dual-phase approach. To date, no studies have compared organ doses and the effective dose (ED) from conventional subtraction scintigraphy, dual-phase MIBI SPECT/CT, and FCH PET/CT in the localisation of HPGs. AIM: In addition to the comparison of the diagnostic performance of FCH PET/CT and conventional scintigraphic imaging methods, the aim of the study was to measure the organ doses and the ED for conventional subtraction parathyroid imaging protocols, using dual-phase MIBI SPECT/CT as a potential conventional imaging method of choice and FCH dual-phase PET/CT as a potential future imaging method of choice for the localisation of HPGs. Materials, methods. Thirty-six patients referred for parathyroid imaging with a clinical indication of PHP underwent preoperative PSS and dual-phase SPECT/CT imaging with the addition of FCH PET/CT. The diagnostic performance of the imaging modalities was assessed by using histology results as a gold standard. Radiation exposure was calculated for the administered activities of radiopharmaceuticals using ICRP80 weighting factors and for CT exposure at hybrid imaging using dose-length products and the ImPACT CT Patient Dosimetry Calculator. RESULTS: The diagnostic performance of FCH PET/CT was significantly better than that of conventional imaging modalities (sensitivity of 97% vs 64% and 46% for MIBI SPECT/CT and PSS, respectively, with comparable specificity of over 95% for all modalities). The highest radiation exposure was caused by conventional PSS (7.4 mSv), followed by dual-phase MIBI SPECT/CT (6.8 mSv). The radiation exposure was the lowest for dual-phase FCH PET/CT imaging (2.8 mSv). The added CT imaging for both hybrid approaches did not cause significant additional radiation exposure (1.4 mSv for MIBI SPECT/CT, additional 26.4% to overall exposure; 0.8 mSv for FCH PET/CT, additional 42.4% to overall exposure). CONCLUSION: In comparison to conventional scintigraphic imaging of HPGs, emerging hybrid (SPECT/CT, PET/CT) imaging techniques combine superior diagnostic performance with lower radiation exposure to patients.

Estimated collective effective dose to the population from radiological examinations in Slovenia.

BACKGROUND: The aim of the study was to systematically evaluate population exposure from diagnostic and interventional radiological procedures in Slovenia. METHODS: The study was conducted in scope of the "Dose Datamed 2" project. A standard methodology based on 20 selected radiological procedures was adopted. Frequencies of the procedures were determined via questionnaires that were sent to all providers of radiological procedures while data about patient exposure per procedure were collected from existing databases. Collective effective dose to the population and effective dose per capita were estimated from the collected data (DLP for CT, MGD for mammography and DAP for other procedures) using dose conversion factors. RESULTS: The total collective effective dose to the population from radiological in 2011 was estimated to 1300 manSv and an effective dose per capita to 0.6 mSv of which approximately 2/3 are due to CT procedures. CONCLUSIONS: The first systematic study of population exposure to ionising radiation from radiological procedures in Slovenia was performed. The results show that the exposure in Slovenia is under the European average. It confirmed large contributions of computed tomography and interventional procedures, identifying them as the areas that deserve special attention when it comes to justification and optimisation.

Quality assured implementation of the Slovenian breast cancer screening programme.

SETTING: The organised, population-based breast cancer screening programme in Slovenia began providing biennial mammography screening for women aged 50-69 in 2008. The programme has taken a comprehensive approach to quality assurance as recommended by the European guidelines for quality assurance in breast cancer screening and diagnosis (4th edition), including centralized assessment, training and supervision, and proactive monitoring of performance indicators. This report describes the progress of implementation and rollout from 2003 through 2019. METHODS: The screening protocol and key quality assurance procedures initiated during the planning from 2003 and rollout from 2008 of the screening programme, including training of the professional staff, are described. The organisational structure, gradual geographical rollout, and coverage by invitation and examination are presented. RESULTS: The nationwide programme was up and running in all screening regions by the end of 2017, at which time the nationwide coverage by invitation and examination had reached 70% and 50%, respectively. Nationwide rollout of the population-based programme was complete by the end of 2019. By this time, coverage by invitation and examination had reached 98% and 76%, respectively. The participation rates consistently exceeded 70% from 2014 to 2019. CONCLUSIONS: The successful implementation of the screening programme can be attributed to an independent central management, external guidance, and strict adherence to quality assurance procedures, all of which contributed to increasing governmental and popular support. The benefits of quality assurance have influenced all aspects of breast care and have provided a successful model for multidisciplinary management of other diseases.

INTERVENTIONAL RADIOLOGICAL PROCEDURES MOST PRONE TO CAUSE HIGH PATIENT PEAK SKIN DOSES BASED ON REVIEW OF 7607 PROCEDURES.

Peak skin doses to patients undergoing interventional radiological procedures in a 3-year period were assessed to identify the most critical procedures and evaluate probability for occurrence of radiation-induced tissue injuries. Data of 7607 patients were reviewed, identifying those with cumulative air kerma at a reference point (Ka,r) exceeding 3 Gy. Observed tissue injuries in patients with exceeded levels were gathered by a questionnaire. Ka,r exceeded 3 Gy in 145 patients, all during vascular procedures; most frequently in preparations for liver radioembolization (SIRT), transjugular intrahepatic portosystemic shunt (TIPS), endovascular abdominal aortic repair (EVAR), adrenal venous sampling (AVS), endovascular thoracic aortic repair (TEVAR) and embolizations in abdominal/pelvic area (30, 21.4, 13.4, 12.6, 9.6 and 3.5% of patients, respectively). A total of 10 patients, extrapolating to ~0.6% of all patients, reported tissue injuries. During interventional radiological procedures threshold for radiation-induces tissue injuries can be exceeded in a significant number of patients (1.9%). Tissue injuries were reported approximately three times less frequently than anticipated; their severity was poorly related to those expected.

Reference levels for image quality in mammography.

Diagnostic reference levels are a well-established tool for optimisation in diagnostic radiology. A dose-reference level for certain diagnostic procedures, meant to identify practices with unusually high doses, is usually set at the third quartile of the distribution of doses in different diagnostic centres. If image quality is somehow quantified, the same 'worst quarter' principle can also be used to identify practices with less than optimal performance in terms of image quality. In Slovenia, the performance of mammographic centres is evaluated annually. Technical testing includes average glandular dose determination and evaluation of technical image quality using the image of a mammographic phantom. From the phantom image, simple image quality parameters are derived and for some of them reference levels can be established. In this study, the results from ten years of testing (1996--2006) at mammography centres are presented and the usefulness of reference levels is evaluated.

Improvement of early detection of breast cancer through collaborative multi-country efforts: Medical physics component.

PURPOSE: The International Atomic Energy Agency (IAEA) through a Coordinated Research Project on "Enhancing Capacity for Early Detection and Diagnosis of Breast Cancer through Imaging", brought together a group of mammography radiologists, medical physicists and radiographers; to investigate current practices and improve procedures for the early detection of breast cancer by strengthening both the clinical and medical physics components. This paper addresses the medical physics component. METHODS: The countries that participated in the CRP were Bosnia and Herzegovina, Costa Rica, Egypt, India, Kenya, the Frmr. Yug. Rep. of Macedonia, Mexico, Nigeria, Pakistan, Philippines, Slovenia, Turkey, Uganda, United Kingdom and Zambia. Ten institutions participated using IAEA quality control protocols in 9 digital and 3 analogue mammography equipment. A spreadsheet for data collection was generated and distributed. Evaluation of image quality was done using TOR MAX and DMAM2 Gold phantoms. RESULTS: QC results for analogue equipment showed satisfactory results. QC tests performed on digital systems showed that improvements needed to be implemented, especially in thickness accuracy, signal difference to noise ratio (SDNR) values for achievable levels, uniformity and modulation transfer function (MTF). Mean glandular dose (MGD) was below international recommended levels for patient radiation protection. Evaluation of image quality by phantoms also indicated the need for improvement. CONCLUSIONS: Common activities facilitated improvement in mammography practice, including training of medical physicists in QC programs and infrastructure was improved and strengthened; networking among medical physicists and radiologists took place and was maintained over time. IAEA QC protocols provided a uniformed approach to QC measurements.